Annular fracturing service tool system

ABSTRACT

An annular fracturing device and method for perforating and annular fracturing multiple zones of a wellbore on a single trip, the annular fracturing device being connected to coiled tubing. The annular fracturing device may include a locating device connected beneath a packing device used to hydraulically isolate a portion of the wellbore. The packing device may be releasably connected to an abrasive perforating device, such as a sand jetting sub. The sand jetting sub may be connected to the bottom of coiled tubing, which is used to run the annular fracturing device into the well bore and to supply the sand jetting sub with abrasive material to perforate the wellbore. The coiled tubing may also supply the sand jetting sub with fluid to circulate out of the sand jetting sub during the fracturing process.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a method and a downhole device (“annular fracturing device”) that can be run on coiled tubing for perforating and annular fracturing multiple zones of a wellbore on a single trip. The annular fracturing device is comprised of a locating device connected beneath a packing device, which is used to hydraulically isolate a portion of the wellbore. The locating device allows the annular fracturing device to be positioned within a zone of interest of the wellbore. A releasable connector connects the packing device beneath an abrasive perforating device, such as a sand jetting sub. The abrasive perforating device may be connected to the bottom of coiled tubing, which runs the annular fracturing device into the well bore and also supplies the abrasive perforating device with pumped abrasive material, such as 20/40 Ottowa sand, that is used to perforate the wellbore. During the fracturing process, the coiled tubing may supply the abrasive perforating device with fluid that may be circulated out of the abrasive perforating device to prevent buildup of proppant on the abrasive perforating device or the packing device and the releasable connector located below the abrasive perforating device. A method is disclosed that provides for the perforation and fracturing of multiple zones of a wellbore during a single trip of the annular fracturing device.

2. Description of the Related Art

Perforating and fracturing a well is common practice in the oil and gas industry in an effort to stimulate the well and increase the production of hydrocarbons. The perforation and fracturing of a well can be a rather time consuming and thus, expensive to perform. Conventional equipment that is used to perforate and isolate a zone of interest of the well often do not allow multiple zones of the well to be stimulated. For example, a perforation gun is often used to perforate the well casing and the rock formation such that the perforations in the formation can then be fractured. Perforation guns generally consist of a series of charges dispersed at various heights and angular orientations along a cylinder. After the perforation gun has been loaded with charges, it is run into the hole and positioned within a zone of interest. The charges are then set off causing multiple perforations through well casing and into the formation. However to perforate another zone of the well, the perforation gun must typically be removed from the well and loaded with new charges. This process limits the number of zones that can be perforated and then fractured in a single day. Thus, it may be beneficial to use a different device that can perforate multiple zones of a well in a single trip.

The isolation of a perforated zone may possibly present another limit to the number of zones that may be stimulated during a single day. After the casing has been perforated, the zone of interest needs to be hydraulically isolated from other portions of the well. This allows fracturing fluid to be pumped at a high pressure into the zone of interest. The high pressure of the fracturing fluid propagates the perforations in the formation, which may increase the production of hydrocarbons from that zone. Fracturing fluid typically contains a proppant that aids in holding the fractures open after the fracturing process has been completed.

A sand plug is one conventional device that is used to hydraulically isolate the zone of interest from lower portions of the well. It often can take at least a couple of hours to build a sand plug that effectively isolates the zone of interest. This build time increases the overall time to perforate and fracture a zone of interest, thus decreasing the number of zones that may be stimulated in a day. Additionally, sand plugs are difficult to build and thus, may not effectively isolate the zone possibly causing poor stimulation as would be recognized by one of ordinary skill in the art. It would be beneficial to utilize a system that is not as difficult to use and may isolate a zone of interest in less time allowing for more zones of a well to be stimulated in a single days work.

Coiled tubing may be used to convey downhole tools into the well that will both perforate a zone of interest and hydraulically isolate the zone of interest. Annular casing fracturing may also be performed while the coiled tubing remains in the wellbore. The use of coiled tubing with a perforation device that does not have to be recharged or replaced between perforations may allow for multiple zones of a well to be stimulated in a single trip, which would decrease the expenses with the stimulation procedures. However, a typical zone that is annular fractured often requires at least 1 to 2 hours of actual stimulation time. In order to decrease the overall time and allow multiple zones to be stimulated in a day, improvements to the perforation and isolation devices used in annular fracturing are needed.

In light of the foregoing, it would be desirable to provide a tool and method to allow multiple zones to be stimulated by annular fracturing in a single trip into the wellbore. Further, it would be desirable to provide an annular fracturing device that decreases the time required to perforate a zone of interest of a wellbore. It would also be desirable to provide an annular fracturing device that can perforate a number of different zones of a wellbore without being removed from the wellbore. It may be desirable to provide a method to perforate and fracture a wellbore using coiled tubing without removing the annular fracturing device from the wellbore prior to the fracturing procedure. It may also be desirable to provide an annular fracturing device that includes a retrievable packing device that hydraulically isolates a zone of the well.

The present invention is directed to overcoming, or at least reducing the effects of, one or more of the issues set forth above.

SUMMARY OF THE INVENTION

The object of the present disclosure is to provide a annular fracturing device and method to perform multiple annular fracturing procedures in a well bore. In one embodiment an annular fracturing device for use with coiled tubing is disclosed, the annular fracturing device comprising a packing device that may be actuated to isolate a portion of a wellbore. The annular fracturing device includes a locating device to determine the position within the wellbore, the locating device being connected beneath the packing device. Alternatively, the locating device may be an integral part of the packing device. The annular fracturing device further includes a sand jetting sub having at least one fluid port, the sand jetting sub is connectable to an end of coiled tubing and the at least one fluid port of the sand jetting sub is in fluid communication with coiled tubing. The annular fracturing device also includes a connecting device connected above the packing device that is also releasably connected beneath the sand jetting sub.

The locating device of the present disclosure may be a collar locator. The connecting device of the present disclosure may be a yo-yo disconnect tool or other downhole disconnect tool. The packing device may be a retrievable bridge plug. In one embodiment the retrievable bridge plug is a cup type retrievable bridge plug. Alternatively, the packing device may be a mechanically set packer or a hydraulically set packer.

One embodiment of the present disclosure is a method of annular fracturing a zone with a wellbore comprising the step of running a downhole assembly into the wellbore on the bottom end of coiled tubing, the downhole assembly comprising a sand jetting sub in fluid communication with the coiled tubing, a releasable connector attached beneath the sand jetting sub, a retrievable packing device connected beneath the releasable connector, and a collar locator. The collar locator may be connected beneath the retrievable packing device or alternatively, may be an integral part of the retrievable packing device. The method includes the steps of locating the packing device below the zone of interest within the wellbore and setting the retrievable packing device below the zone of interest. The method further includes the steps of releasing the releasable connector from the sand jetting sub and moving the sand jetting sub up the wellbore to the zone of interest, wherein the sand jetting sub has at least one exterior port in fluid communication with the coiled tubing. The method include the steps of pumping abrasive material down the wellbore and through the exterior port of the sand jetting sub to perforate the wellbore at the zone of interest and moving the sand jetting sub below the zone of interest. The method further includes the step of pumping fracturing fluid down the annulus between the wellbore and the coiled tubing. The sand jetting sub is moved below the zone of interest to allow a sufficient annular flow path for the fracturing fluid to the zone of interest as would be recognized by one of ordinary skill in the art having the benefit of this disclosure.

The method may further include the step of pumping fluid down the coiled tubing and through the exterior port of the sand jetting sub while pumping the fracturing fluid down the annulus between the wellbore and the coiled tubing. The releasable connector used in the disclosed method may be a yo-yo disconnect tool. Alternatively, the releasable connector may be any connector that may be released using coiled tubing as would be appreciated by one of ordinary skill in the art having the benefit of this disclosure.

The packing device of the disclosed method may be a retrievable bridge plug. Further, the retrievable bridge plug may be a cup type retrievable bridge plug. Alternatively, the packing device may be any device, such as a mechanically or hydraulically set packer, that may be actuated to hydraulically isolate a portion of the wellbore as would be recognized by one of ordinary skill in the art having the benefit of this disclosure.

One embodiment of the present disclosure is an apparatus for use on coiled tubing in annular fracturing, the apparatus comprising means for hydraulically isolating a portion of a wellbore and means for locating a specified location of the wellbore, the means for locating being connected beneath the means for hydraulically isolating a portion of the wellbore. Alternatively, the means for locating may be a part of the means for hydraulically isolating a portion of the wellbore. The apparatus further comprises means for abrasively perforating a portion of the wellbore, the means for abrasively perforating being connected to coiled tubing and being releasably connected above the means for hydraulically isolating a portion of the wellbore. The apparatus also comprises means for releasing the means for abrasively perforating from above the means for hydraulically isolating a portion of the wellbore.

In one embodiment the means for hydraulically isolation a portion of a wellbore may be actuated by differential pressure. Alternatively, the means for hydraulically isolation a portion of the wellbore may be mechanically or hydraulically actuated. The means for releasing the means for abrasively perforating may be released pulling up on the coiled tubing. For example, the releasing means may comprise a yo-yo disconnect tool or other releasable connector.

One embodiment of the present disclosure is a method of annular fracturing a zone in well tubing within a wellbore comprising running a downhole assembly into the well tubular on the bottom end of coiled tubing, the downhole assembly comprising a sand jetting sub in fluid communication with the coiled tubing, a releasable connector attached beneath the sand jetting sub, a retrievable packing device connected beneath the releasable connector, and a collar locator connected beneath the retrievable packing device. The method includes locating the packing device below the zone of interest within the well tubular and setting the retrievable packing device below the zone of interest. The method further includes selectively releasing the releasable connector from the sand jetting sub and moving the sand jetting sub up the well tubular to the zone of interest, wherein the sand jetting sub has at least one exterior port in fluid communication with the coiled tubing. The method includes pumping abrasive material down the wellbore and through the exterior port of the sand jetting sub to perforate the well tubular and the wellbore at the zone of interest and moving the sand jetting sub below the zone of interest. The method further includes pumping fracturing fluid down the annulus between the well tubular and the coiled tubing. The method may further include moving the sand jetting sub above the zone of interest into a portion of the well having a larger diameter that the well tubular to allow a sufficient annular flow path for the fracturing fluid to the zone of interest as would be appreciated by one of ordinary skill in the art having the benefit of this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows one embodiment of an annular fracturing device on the end of coiled tubing 10 above a first zone of interest 100 that has previously been perforated and fractured.

FIG. 2 shows the annular fracturing device of FIG. 1 beginning to perforate the well at a new zone of interest.

FIG. 3 is shows the sand jetting sub 30 of the annular fracturing device moved below the perforations 200 prior to fracturing the new zone of interest.

FIG. 4 is a cross-section view of collar locator 60 positioned within a collar 70 of the well casing.

While the invention is susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in detail herein. However, it should be understood that the invention is not intended to be limited to the particular forms disclosed. Rather, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the invention as defined by the appended claims.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Illustrative embodiments of the invention are described below as they might be employed in the method of perforating and annular fracturing a wellbore with an annular fracturing device connected to the bottom of coiled tubing that allows for multiple zones to be abrasively perforated and fractured in a single trip into the well. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the are having the benefit of this disclosure.

Further aspects and advantages of the various embodiments of the invention will become apparent from consideration of the following description and drawings.

FIG. 1 shows one embodiment of the annular fracturing device of the present disclosure that includes a collar locator 60, a retrievable bridge plug 50, a yo-yo disconnect tool 40, and a sand jetting sub 30. The collar locator 60 is connected beneath the retrievable bridge plug 50 and is used to determine when the assembly is within a particular zone of interest in the well based on collars 70 located in the well casing 20. Although the embodiment of FIG. 1 includes a collar locator, this device may be one of a various number of downhole devices used to determine the location of a downhole assembly within a wellbore. After being properly positioned, the retrievable bridge plug 50 is then set to hydraulically isolate the zone of interest. A cup type retrievable bridge plug may be preferred in this application as a cup type retrievable bridge plug may be set by using differential pressure from either above or below the plug. Also a cup type retrievable bridge plug may be ideal for this application because the plug may be released by merely pulling up with the coiled tubing. Although the embodiment of FIG. 1 includes a retrievable bridge plug, one of ordinary skill in the art having this disclosure would appreciate a number of different packing devices that may be run and set with coiled tubing which may be used with the annular fracturing device to isolate a zone within the wellbore.

Once the retrievable bridge plug 50 has been set, the sand jetting sub 30 may be released from the bridge plug 50. In one embodiment, a yo-yo disconnect tool 40 is used to releasably connect the sand jetting sub 30 to the bridge plug 50. A yo-yo disconnect tool 40 may be ideal for this application because it releases the sand jetting sub 30 simply by picking up on the coiled tubing 10, but a different releasable connector may be used with the annular fracturing device as would be appreciated by one of ordinary skill in the art having the benefit of this disclosure.

After the sand jetting sub 30 has been released from the bridge plug 50, the sand jetting sub 30 is moved up the casing 20 to the location within the zone of interest that is to be perforated as shown in FIG. 2. Once the sand jetting sub 30 is positioned at the proper location, an abrasive laden fluid may be pumped at a high pressure down the coiled tubing 10 and through the jetting ports 35 on the exterior of the sand jetting sub 30. For example, 20/40 Ottowa sand may be pumped through the sand jetting sub 30 to perforate 200 the casing 20 at the desired location as shown in FIG. 2. Using 20/40 Ottowa sand pumped through the sand jetting sub 30 may perforate the casing at the zone of interest in as little as twenty minutes. The configuration of the jetting ports 35 of the sand jetting sub 30 may be varied to change the number and locations of perforations created by the sand jetting sub 30. The configuration of the individual jetting ports 35 may also be changed to modify the cutting power of the sand jetting sub 30.

After the casing or tubular has been perforated, the coiled tubing is run down the casing 20 until the sand jetting sub 30 is located below the perforations 200 in the zone of interest. Alternatively, the sand jetting sub 30 may be move up the wellbore to a location that has a larger diameter than the zone of interest. The sand jetting sub 30 is moved away from the perforations 200 to provide a sufficient annular flow path to allow stimulation of the perforations 200. Fracturing fluid may then be pumped down the annulus 15 between coiled tubing 10 and the casing 20. Fracturing fluid is pumped down at a high pressure in an attempt to propagate the perforations 200 in the zone of interest into fractures 300 in the formation as shown in FIG. 3. The set bridge plug 50 isolates the zone and aids in allowing the high pressure fracturing fluid to propagate the fractures in the formation. Fluid may be pumped down the coiled tubing 10 and circulated out of the jetting ports 35 while fracturing fluid is being pumped down the annulus 15. The fluid circulated out of the jetting ports 35 may help to prevent proppant located in the fracturing fluid from accumulating on the jetting sub 30 or downhole on the disconnect tool 40 and the bridge plug 50.

After the zone of interest has been stimulated, the sand jetting sub 30 may then be re-connected to the yo-yo disconnect tool 40 and the bridge plug may be deactivated allowing the pressure in the zone of interest to equalize with the well pressure below. The annular fracturing device may then be positioned in the next zone of interest using the collar locator 60. Once properly position in the new location, the bridge plug 50 may again be set hydraulically isolating the new zone of interest. After the bridge plug 50 is set, the yo-yo disconnect tool 40 releases the sand jetting sub 30 which is moved up to perforate the casing 20 in a designated location. The configuration of this annular fracturing device allows multiple zones of a well to be perforated and fractured in a single trip. FIG. 4 is a cross section of the collar locator 60 positioned within a collar 70 of the well casing 20. As discussed above, the collar locator 60 allows the coiled tubing operator to position the annular fracturing device within a desired zone of the wellbore.

Although various embodiments have been shown and described, the invention is not so limited and will be understood to include all such modifications and variations as would be apparent to one skilled in the art. 

1. An annular fracturing device for use with coiled tubing, the device comprising: a packing device, wherein the packing device may be actuated to isolate a portion of a wellbore; a locating device to determine the position of the annular fracturing device within the wellbore; a sand jetting sub having at least one fluid port on the exterior, wherein the sand jetting sub is connectable to an end of coiled tubing and the at least one fluid port of the sand jetting sub is in fluid communication with the coiled tubing; and a connecting device connected above the packing device, wherein the connecting device is releasably connected beneath the sand-jetting sub.
 2. The device of claim 1, wherein the locating device is connected beneath the packing device.
 3. The device of claim 2, wherein the locating device comprises a collar locator.
 4. The device of claim 1, wherein the locating device is a part of the packing device.
 5. The device of claim 1, wherein the connecting device is a yo-yo disconnect tool.
 6. The device of claim 1, wherein the packing device is a retrievable bridge plug.
 7. The device of claim 6, wherein the retrievable bridge plug is a cup type retrievable bridge plug.
 8. The device of claim 1, wherein the packing device is a mechanically or hydraulically set packer.
 9. A method of annular fracturing a zone within a wellbore, the method comprising the steps of: running a downhole assembly into the wellbore on the bottom end of coiled tubing, the downhole assembly comprising, a sand jetting sub in fluid communication with the coiled tubing, a releasable connector attached beneath the sand jetting sub, a retrievable packing device connected beneath the releasable connector, and a collar locator connected beneath the retrievable packing device; locating the packing device below the zone of interest within the wellbore; setting the retrievable packing device below the zone of interest; releasing the releasable connector from the sand jetting sub; moving the sand jetting sub up the wellbore to the zone of interest, wherein the sand jetting sub has at least one exterior port in fluid communication with the coiled tubing; pumping abrasive material down the coiled tubing and through the exterior port of the sand jetting sub to perforate the wellbore at the zone of interest; moving the sand jetting sub to provide an annular flow path to the wellbore perforations; and pumping fracturing fluid down the annulus between the wellbore and the coiled tubing.
 10. The method of claim 9, wherein the sand jetting sub is moved above the wellbore perforations into a portion of the wellbore having a larger diameter than the zone of interest.
 11. The method of claim 9, wherein the sand jetting sub is moved below the wellbore perforations.
 12. The method of claim 11 further comprising pumping fluid down the coiled tubing and through the exterior port of the sand jetting sub while pumping fracturing fluid down the annulus between the wellbore and the coiled tubing.
 13. The method of claim 9, wherein the releasable connector is a yo-yo disconnect tool.
 14. The method of claim 9, wherein the packing device is a retrievable bridge plug.
 15. The method of claim 14, wherein the retrievable bridge plug is a cup type retrievable bridge plug.
 16. The method of claim 9, wherein the packing device is a mechanically or hydraulically set packer.
 17. An apparatus for use on coiled tubing in annular fracturing, the apparatus comprising: means for hydraulically isolating a portion of a wellbore; means for locating a specified location of the wellbore; means for abrasively perforating a portion of the wellbore, the means for abrasively perforating being connected to coiled tubing and being releasably connected above the means for hydraulically isolating a portion of a wellbore; and means for selectively releasing the means for abrasively perforating from above the means for hydraulically isolating a portion of the wellbore.
 18. The apparatus of claim 17, wherein the means for locating a specified location of the wellbore is connected beneath the means for hydraulically isolating a portion of the wellbore.
 19. The apparatus of claim 17, wherein the means for locating a specified location of the wellbore is a part of the means for hydraulically isolating a portion of the wellbore.
 20. The apparatus of claim 17, wherein the means for hydraulically isolating a portion of a wellbore is actuated by differential pressure.
 21. The apparatus of claim 17, wherein the means for hydraulically isolating a portion of the wellbore is mechanically or hydraulically actuated.
 22. The apparatus of claim 17, wherein the releasing means releases due to pulling up on the coiled tubing.
 23. A method of annular fracturing a zone in a well tubular within a wellbore, the method comprising the steps of: running a downhole assembly into the well tubular on the bottom end of coiled tubing, the downhole assembly comprising, a sand jetting sub in fluid communication with the coiled tubing, a releasable connector attached beneath the sand jetting sub, a retrievable packing device connected beneath the releasable connector, and a collar locator connected beneath the retrievable packing device; locating the packing device below the zone of interest within the well tubular; setting the retrievable packing device below the zone of interest; releasing the releasable connector from the sand jetting sub; moving the sand jetting sub up the well tubular to the zone of interest, wherein the sand jetting sub has at least one exterior port in fluid communication with the coiled tubing; pumping abrasive material down the coiled tubing and through the exterior port of the sand jetting sub to perforate the well tubular and the wellbore at the zone of interest; moving the sand jetting sub to provide an annular flow path to the well tubular and wellbore perforations; and pumping fracturing fluid down the annulus between the well tubular and the coiled tubing.
 24. The method of claim 23, wherein the sand jetting sub is moved above the well tubular and wellbore perforations into a portion of the wellbore having a larger diameter than the well tubular.
 25. The method of claim 23, wherein the sand jetting sub is moved below the well tubular perforations.
 26. The method of claim 25 further comprising pumping fluid down the coiled tubing and through the exterior port of the sand jetting sub while pumping fracturing fluid down the annulus between the well tubular and the coiled tubing 